The following are the new old stock Vintage Citizen 51-2273 diver watches from Jan 1980 & Feb 1980. From the outward view, both looks similar. In vintage watch collection, sometimes the difference is in the small details. The prices can varies according to these small details
Looking similar
There are dial differences with one stating Citizen Automatic, 21 Jewels Water Resistant 150M vs
Citizen Automatic, Water Resistant 150M (without the 21 Jewels)
The Date disc showing one with JApanese wordings
One is 17 Jewels vs 21 Jewwels
Finally, one is slightly thinner then the other
In summary, the Jan 1980 watch is slightly thicker than the Feb 1980 issued one, plus it is made for the Japanese market and it has 21 Jewels vs 17 jewels for the International market.
